As is well known, an organic EL element has a basic structure including a first electrode (an anode or cathode), a second electrode (a cathode or anode), and an organic light-emitting layer provided between these electrodes. In such a structure, when a current is allowed to flow between the electrodes facing each other with the organic light-emitting layer interposed therebetween, the organic light-emitting layer emits light.
The applications of organic EL elements include display devices and lighting devices. In a display device, a plurality of organic EL elements are arranged on a substrate, and each organic EL element functions as a pixel (see, for example, Patent Document 1). The size of the organic EL elements for such a display device is determined according to the required resolution, and generally the width and length of each organic light-emitting layer used therein is of micrometer order. On the other hand, for a lighting device, it is not necessary to use such a small size of organic EL elements as in display devices, and one or a plurality of organic EL elements including an organic light-emitting layer of which width and length are of centimeter order are arranged on a substrate.
Patent Document 1 JP 2006-286243 A